The doors of ovens, refrigerators and microwaves etc. have tubular gaskets around their perimeter for sealing and a variety of other reasons. This gasket is typically made of a combination of an inner tubular support member formed of knitted wire and an outer tubular member made either by braiding, knitting or weaving an insulating material such as fiberglass yarn. Such structures have proven to be durable at high temperatures used in self-cleaning ovens and provided a good sealing despite repeated openings and closures of the oven door over many years of use.
Methods of attaching a tubular gasket to oven door surface have typically comprised of providing several individual clip fasteners which extends along the gasket axial. Clip fasteners have heads and bases which are perpendicular to one another. Bases are embed into the gasket while heads projected out from gasket and inserted into the hole of the oven door to mount the gasket onto the oven door.
Several clip fasteners are presented in prior arts. For example, U.S. Pat. No. 6,893,025 presents a kind of gasket apparatus with clip fasteners. A clip fastener coming from a strand of elastic metal wire bent in a certain angle includes a diamond-shaped head and a base which is perpendicular to the plane of the head. The base comprises at least one coil course having a variable or constant radius of curvature and one tail. The tail typically bents downwards and separates from the last coil course. During many years of use, it is found that hands of operator are easily to be pricked when mounting gasket because of the up-wrapped tail. In addition, fiberglass is also easily to be pierced or lacerated which causes bad performance of gasket. Furthermore, as there is a tail in the clip, it is hard to be embedded into gasket when weaving. It has to be embedded into woven gasket by rotating and it is labor intensive process. When the base of clip fastener is more than one loop coil course, the multi-coil will easily cause the silk-spinning of fiberglass and affect sealing.
U.S. Pat. No. 5,107,623 presents a kind of loom-type weaving clip fastener which avoids intensive labor when rotating the clip fastener into gasket, but it brings another problem. As soon as the clip fastener is woven into gasket, it is hard to extract it again unless forced extraction. However, forced extraction will destroy the woven structure of fiberglass and bring heavy affection to sealing. When using this kind of clip, if any step is taken incorrectly, for example, wrong separation between clip fasteners or clip fasteners not in a line, total gasket will be rejected.
When mounting clip fasteners to gasket, clip fastener is mounted to gasket when fiberglass sheath is being woven. For example, in U.S. Pat. No. 6,533,289, an equipment for weaving fiberglass sheath weaves fiberglass sheath mounting clip fastener while weaving fiberglass sheath. In existing arts, most equipments take simple change or manual operation based on the equipment for weaving fiberglass sheath and the efficiency is low.